1. Field of the Invention
The present invention relates to a circuit breaker, and more particularly, to a pressure trip device for a circuit breaker capable of faster tripping a circuit breaker by using a pressure of arc gas generated when a movable contactor and a fixed contactor are separated from each other by an electromagnetic repulsive force.
2. Description of the Related Art
FIGS. 1 and 2 are respectively a lateral view and a perspective view of a circuit breaker in accordance with the conventional art.
As shown in FIGS. 1 and 2, the conventional circuit breaker constituted with a single pole switching unit 22 comprises an outer case 21 for protecting a mechanism, a magnetic core 25 installed in the outer case 21 for generating an electromagnetic force proportionally to an electrical current flowing on the circuit breaker, an armature 26 attracted by the magnetic core 25, a cross bar 27 actuated by the armature 26, a trip shooter 28 actuated by the cross bar 27, a spring 29 for providing a driving force to the trip shooter 28, and a trip bar 24 being rotated by the trip shooter 28 for triggering the switching mechanism of the circuit breaker to a position of trip.
FIG. 3 is a view showing a locked state of a trip shooter for the circuit breaker of FIG. 1, FIG. 4 is an enlarged view of a part ‘A’ in FIG. 3, FIG. 5 is a view showing a released state of the trip shooter for the circuit breaker of FIG. 1, and FIG. 6 is an enlarged view of a part ‘B’ in FIG. 5.
Referring to FIGS. 3 and 4, in the conventional circuit breaker, the trip shooter 28 is locked by the cross bar 27 when a normal current flows, and thus the trip bar 24 maintains a reset position.
Referring to FIGS. 5 and 6, an electromagnetic force of the magnetic core 25 pulls the armature 26 when a large current such as short circuit current is generated.
Upper end of the pulled armature 26 pushes the cross bar 27 to rotate clockwise, thereby releasing a hooked portion 28a of the trip shooter 28 locked by a hook 27a of the cross bar 27.
The trip shooter 28 is counterclockwise rotated by an elastic force of the spring 29, and rotates the trip bar 24 clockwise. Accordingly, a not shown latch is released by the rotation of the trip bar 24 and the switching mechanism of the circuit breaker is driven to a position of trip by a not shown trip spring.
However, the conventional circuit breaker has the following problems. Since the conventional circuit breaker is tripped by a process using mechanisms of a multi-step, arc energy is drastically increased due to a time delay at the time of an occurrence of an electric shortage current. The drastic arc energy increase damages a body and a mechanic part of the circuit breaker and fuses a movable contactor (not shown) and a fixed contactor (not shown) to each other, thereby degrading a reliability of the circuit breaker.